Abstract: It has been suggested previously that the observed cosmological constantLambda corresponds to the remnant vacuum energy density of dynamical processestaking place at a cosmic age set by the mass scale M \sim E {ew} ofultramassive particles with electroweak interactions. Here, a simplemodification of the nondissipative dynamic equations of q-theory is presented,which produces a remnant vacuum energy density effective cosmologicalconstant of the correct order of magnitude. Combined with the observed valueof Lambda, a first estimate of the required value of the energy scale E {ew}ranges from 3 to 9 TeV, depending on the number of species of ultramassiveparticles and assuming a dissipative coupling constant of order unity. Ifcorrect, this estimate implies the existence of new TeV-scale physics beyondthe standard model.